


c I 









■ 












iwVv ..: 

I 
■ 

■ ■ 






■ 



.{',-• *U ' 



■ 

I m I 

■ ■ i 

I 

I 









^H 



■ 






■ 

■ 

I ■ I 

■ I ■■:•■»*;<■■ H 



^^^ 



■ 



w 










° "V C~> 



u»V 




a^ 




<* '*•'•»*' .A* ^L, **T7T** A 

'.c^r.X >°*,.^sit.% JPslaL-X 




*5* ,\> 




^^ 



^f :£U^** "*W °V^» "^<? y£jm^\ **^ 



^ 








o#. ♦•. 







.g v \d **tC7* a <+ 






• A V "V »" 







«> *.;<>»* V^ 



o_ * 




.0 

















V* 








*>-. 







"- *W r«^sla : : ^v^ 



V*-- T V J "^'•^'••y %^^^/ V^\/ V^^%°° V^-M 



^ 'A <V 



J ^ 






*>o^ 



"oV 








': ^^ v 










V*\ 



^ ^ ".Ye- ^ O *.,,.' ,0' 









vj> A 












V A * 







*^* 






.V 



'V 



» .tl^.\ ^ c° 










■?■ V * ' * °» ^v 



A^ ^ w ♦OTr** A <, 

o V 




r.--^ 













4 a* ^ WW ,^ ^ * 










V"' ^"<^ " • » ,A' 




V^ 1 



.v^ 






■-!«••.♦***. 



"«> ''"'* ,, A G ^i, *'VVi* A <\ 'o~A»*' V "o, *-TVT* A ^ m»- .« 



<^_ 



•^v v^v v»> v^v V»v 



*** A*' 














V .*1^* <Z* aO 




v ^ ° - 












^°* 








A> 



\* 



-of 




\ /tidfey* ^slMkS ^*iwk°* / •" 






w> : ** 



V ^ 



<, 



4 V <* • 




^^iPo ,<,^ lW§M$» aV-*> 







^ 1 c 



k " 1 A 







V v ..J^L'* *o 










\/ 













%/ 



V v ,^*^% <\ 







^ v m--;\/ 





** a?% -ISM* c^^p c 

^ * '^^^\\^ ,5 k , ' "?"v .0 *." 






/... \^y \-^^\/ v^V V"v °°* 




















r/ ^ ^ A °^^JC 



^"^ 









if 

^9 




.* ^ 







v *S> j . ' • * s <c> 










r. s * ,G V 



*o. 






*bV° 






<*> <^ s»» *^-v " rt ^" "** "' \ V ' "^* ' " " ° " A u "*>■ "»/i* -A*" 






Bureau of Mines Information Circular/1987 



Human Factors Contributing to 
Groundfall Accidents in 
Underground Coal Mines: 
Workers' Views 

By Robert H. Peters and William J. Wiehagen 



UNITED STATES DEPARTMENT OF THE INTERIOR 



Information Circular 9127 



Human Factors Contributing to 
Groundfall Accidents in 
Underground Coal Mines: 
Workers' Views 

By Robert H. Peters and William J. Wiehagen 




UNITED STATES DEPARTMENT OF THE INTERIOR 
Donald Paul Hodel, Secretary 

BUREAU OF MINES 
Robert C. Horton, Director 



As the Nation's principal conservation agency, the Depu. + ment of the Interior has 
responsibility for most of our nationally owned public lands a. ' " , atural resources. This 
includes fostering the wisest use of our land and water resource.-, protecting our fish 
and wildlife, preserving the environment and cultural values of our national parks and 
historical places, and providing for the enjoyment of life through outdoor recreation. 
The Department assesses our energy and mineral resources and works to assure that 
their development is in the best interests of all our people. The Department also has 
a major responsibility for American Indian reservation communities and for people who 
live in island territories under U.S. administration. 







Library of Congress Cataloging-in-Publication Data 



Peters, Robert H. 

Human factors contributing to groundfall accidents in underground 
coal mines. 



(Information circular ; 9127) 

Includes bibliographical references. 

Supt. of Docs, no.: I 28.27: 

1. Ground control (Mining). 2. Coal mines and mining— United States— Accidents. 
I. Wiehagen, William J. II. Title, in. Series: Information circular (United States. Bureau 
of Mines) ; 9127. 



-TN295.U4 [TN288] 



622 s 



[622 '.334] 



86-600355 



CONTENTS 



in 



Page 

Abstract 1 

Introduction 2 

Barriers to miners' prevention of groundfall 

accidents 2 

Inability to recognize groundfall hazards 2 

Inability to correct groundfall hazards 3 

Motivation to search for groundfall hazards .... 3 

Motivation to correct groundfall hazards 3 

Methods of data collection 4 

Sample 4 

Interviews 4 

Findings 4 

Nonresponse to possible roof hazards 5 

Open-ended questions 5 

Forced-choice questions 5 

Why miners sometimes walk beneath 

unsupported roof 7 

Open-ended questions 7 

Forced-choice questions 8 

Reasons for walking under unsupported 

roof 8 

Precautionary behavior 9 

Proportion and frequency of miners walking 



beneath unsupported roof 9 

Opinions on various measures for preventing 

groundfall accidents 10 

Open-ended questions 10 

Forced-choice questions H 

Miners' experiences with rock falls 14 

Experiences reported by the miners in this 

study 14 

Injured 14 

Not injured 14 

National statistics 14 

Analysis of data from MSHA fatality reports ... 16 

Discussion 16 

Barriers to groundfall accident prevention 17 

Inability to recognize hazards 17 

Inability to correct hazards 17 

Motivation to search for hazards 17 

Motivation to correct hazards 17 

Walking beneath unsupported roof 17 

Miners' and inspectors' recommendations for 

preventing groundfall accidents 18 

Miners' experiences with groundfall accidents . . 18 

Appendix.— Roof fall interview guide for miners . . 19 



ILLUSTRATIONS 

1. Barriers to miners' prevention of groundfall accidents 



TABLES 

1. Breakdown of mine employees interviewed, by job title 4 

2. Rank ordering of reasons for neglect of roof fall hazards 7 

3. Rank ordering of reasons why miners go beneath unsupported roof 9 

4. Estimates of percentage of miners who go beneath unsupported roof during a typical month 10 

5. Estimates of frequency with which someone in a typical crew of miners goes beneath unsupported roof 10 

6. Rank ordering of responses about degree to which various changes would help miners avoid rock fall injuries 13 

Breakdown of— 

7. Groundfall accidents (1980-84), by location 15 

8. Injuries and fatalities caused by rock falls (1980-84), by activity 15 

9. Injuries and fatalities caused by rock falls (1980-84), by job title 15 

10. Injuries caused by rock falls (1980-84), by experience as a miner and experience in current job classification . 15 

11. Injuries caused by rock falls (1980-84), by time elapsed since the shift began 16 

12. Fatalities caused by rock falls (197S-80), by activity 16 



UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 



h 
min 



hour 
minute 



pet 

yr 



percent 
year 



HUMAN FACTORS CONTRIBUTING TO GROUNDFALL ACCIDENTS IN 
UNDERGROUND COAL MINES: WORKERS' VIEWS 



By Robert H. Peters 1 and William J. Wiehagen 2 



ABSTRACT 



This report presents findings from a Bureau of Mines study on barriers that 
may prevent miners from correcting and avoiding groundfall hazards. Such barriers 
stem from four basic types of problems: (1) inability to recognize groundfall hazards, 
(2) inability to correct groundfall hazards, (3) lack of motivation to search for 
groundfall hazards, and (4) lack of motivation to correct groundfall hazards. Data 
are presented that summarize the views of miners, section supervisors, and mine 
inspectors about the contribution of these barriers to groundfall accidents and what 
they think should be done to reduce the frequency of injuries sustained by falls 
of roof and rib. The report also includes a summary of miners' responses concerning 
their recent experiences with groundfall accidents, along with industrywide 
statistics on accidents and injuries caused by ground falls in underground coal 
mines. 



'Research psychologist. 
"Supervisory industrial engineer. 
Pittsburgh Research Center, Bureau of Mines, Pittsburgh, PA. 



INTRODUCTION 



In many underground coal mines, the economic costs 
associated with falls of roof and rib are a substantial 
proportion of the total costs of operating the mine. During 
the 5-yr period, 1980-84, 16,352 groundfall accidents were 
reported to the Mine Safety and Health Administration 
(MSHA). 

These accidents often require that labor, supplies, and 
equipment be diverted from coal production and used for 
cleanup, recovery and repair of mine equipment, and 
resupport of the mine roof. The costs of these activities are 
quite substantial. But of even greater significance are the 
financial and intangible losses and the emotional anguish 
suffered by the families of miners who have been killed or 
seriously disabled by groundfalls. During 1980-84, 
groundfall accidents claimed the lives of 181 coal miners 
and caused 5,323 nonfatal injuries. According to the 
Accident Cost Indicator Model, the direct cost of these 
fatalities and injuries exceeded $200 million. 3 

Although the number of coal miners killed by 
groundfalls has greatly declined since the first half of this 
century, groundfall fatalities continue to occur with 
alarming frequency and are the most common cause of 
accidental death among underground coal miners. During 
1980-84, groundfalls claimed the lives of underground coal 
miners at an average rate of one fatality every 10 calendar 
days. During the same period, the average number of 
miners who suffered a lost-time injury caused by a 
groundfall accident was 914.2 per year, and the average 
number of scheduled workdays lost as a result of these 
injuries was 35.3 days. Clearly, the need to further reduce 
the number of miners being injured and killed by groundfall 
accidents is great. 

The Bureau of Mines performed the research described 
in this report to (1) better define the types of barriers that 



3 DiCanio, D. G„ A. H. Nakata, D. Colvert, and E. LaVeque. Accident Cost 
Indicator Model to Estimate Costs to Industry and Society From Work- 
Related Injuries and Deaths in Underground Coal Mining (contract 
J0255031, FMC Corp.). Volume 3: Supporting Data. BuMines OFR 39(3)-77, 
1976, 104 pp.; NTIS PB 264 440. 



prevent miners from correcting or avoiding groundfall 
hazards, (2) provide a data base and direction for future 
research, and (3) identify promising approaches for prevent- 
ing groundfall accidents. Interviews were conducted with 
(1) various personnel from three underground coal com- 
panies (nine sites) and (2) MSHA coal mine roof and rib in- 
spectors. Interviewers used a structured interview guide 
(which is reproduced in the appendix to this report). 

The long-range goal of this research program is to find 
effective strategies and methods for making miners will- 
ing and able to prevent or avoid groundfalls. The final step 
in the program will be to empirically test hypotheses such 
as: The use of strategy X leads to a significantly lower prob- 
ability of groundfall accidents; or, the use of strategy X leads 
to a significantly lower probability of groundfall accidents 
than strategy Y under conditions A, B, and C. 

One of the initial steps toward achieving this goal is 
to formulate hypotheses. In order to formulate good 
hypotheses about how to prevent groundfall accidents, it 
is important to understand why many groundfall accidents 
occur even though it may appear or actually be the case 
that miners could have prevented or avoided the ground- 
fall. Researchers need to understand the sequence of events 
and the circumstances that lead to these accidents. They 
need to understand what the key variables and processes 
are. Unfortunately, researchers do not yet have a good 
understanding of these key variables and processes. 

One of the best ways to develop such an understanding 
is to determine what those who work in mines understand 
and/or Relieve about the causes of groundfall accidents. 
Therefore, the purpose of this study is not to collect data 
that can be statistically tested to determine the effectiveness 
of strategies for preventing groundfall accidents. The pur- 
pose of the data collected for this study is to improve re- 
searchers' and mine operators' understanding of what those 
who work underground believe about the causes of ground- 
fall accidents. It is hoped that this information will help 
future researchers formulate intelligent hypotheses about 
what strategies would be effective in preventing ground- 
fall accidents. 



BARRIERS TO MINERS' PREVENTION OF GROUNDFALL ACCIDENTS 



Geological factors relevant to the inherent stability of 
the roof and rib influence the likelihood of a groundfall ac- 
cident. Although geological history cannot be changed, 
there are several other factors that influence the probability 
of groundfall accidents over which people potentially have 
some control. This study focuses primarily on (1) assessing 
the measures miners can potentially take to avoid ground- 
fall accidents and (2) gaining a better understanding of the 
types of barriers that prevent them from taking these 
measures. 

Figure 1 presents a conceptual framework for address- 
ing these barriers. The model assumes that in order for 
miners to do an effective job of preventing groundfall in- 
juries, they must not only recognize the existence of the 
hazard but also be willing and able to take corrective ac- 
tion. Barriers can be differentiated on the basis of whether 



they occur at the stage of hazard recognition or hazard cor- 
rection, and on the basis of whether they are due to miners' 
lack of ability or lack of motivation. The primary causes 
for each of the four categories of barriers are discussed 
below. 



INABILITY TO RECOGNIZE GROUNDFALL 
HAZARDS 

In order for miners to recognize a groundfall hazard, 
they must be able to detect it. Miners with poor eyesight 
or miners working in areas with insufficient illumination 
may be unable, for example, to detect cracks associated with 
dangerously loose roof or rib. Miners with hearing deficien- 
cies, or those who work in areas with high noise levels, may 



Stage of barrier s occurrence 



Source of 
barrier 

Ability 



Recognition 



Correction 



Motivation 



Inability to 

recognize 

groundfall hazards 


Inability to 

correct 

groundfall hazards 


Lack of motivation 

to search for 
groundfall hazards 


Lack of motivation 
to correct 

groundfall hazards 



Figure 1 .—Barriers to miners' prevention of groundfall accidents. 



be unable to detect sounds that may accompany an impend- 
ing groundfall. Some miners may be able to perceive the 
visual and auditory cues commonly associated with some 
groundfall hazards, but, due to a lack of experience or train- 
ing, have not learned to relate these cues to the impending 
fall. 



INABILITY TO CORRECT GROUNDFALL 
HAZARDS 

In order for miners to prevent groundfall accidents, they 
must not only be able to recognize the hazard, they must 
also be able to take the necessary corrective actions. Miners 
must be properly trained to scale the roof, set temporary 
roof supports, and perform other ground control activities. 
In addition to having the ability to correct the problem, 
miners must also be provided with sufficient time and 
resources (tools and supplies) to take the appropriate action. 

MOTIVATION TO SEARCH FOR GROUNDFALL 
HAZARDS 

Unfortunately, groundfall hazards are not always 
located where they can be easily seen. It is therefore im- 
portant that miners devote some extra effort to visually 
search for roof and rib hazards. One determinant of a 
miner's motivation to search for such hazards is his or her 
perception of the danger that groundfalls represent. 

The greater a miner's fear of groundfalls and the greater 
the perceived probability of a groundfall occurring, the 
higher will be the motivation to search for hazardous roof 
and rib. Another determinant of a miner's motivation to 
search for such hazards is the extent to which management 



encourages miners to prevent groundfall accidents. Miners 
will be more likely to search for hazardous rock conditions 
if their supervisor makes it clear that this is an important 
aspect of the job. 



MOTIVATION TO CORRECT GROUNDFALL 
HAZARDS 

Even if a groundfall hazard is recognized and the miner 
is able to correct it, the hazard will not be corrected unless 
the miner is sufficiently motivated to do so. A miner's 
motivation to correct groundfall hazards is influenced by 
many factors, including the two mentioned above: perceived 
danger and perceived importance to management. Percep- 
tions of danger encompass both the perceived probability 
of a roof or rib failure as well as the perceived extent or 
degree of damage the fall could cause. Perceptions of the 
likelihood of a groundfall are derived from the miner's past 
experience with groundfalls and from cues associated with 
the stability of the rock being examined, such as the absence 
of adequate support or the presence of severe cracks. 

Perceptions of the amount of damage the rock would 
cause if it fell are probably derived from exposure to the 
effects of past groundfalls and the location of the hazard 
in question. Hazardous roof and rib are less likely to be 
tolerated in areas where people and equipment are fre- 
quently traversed than if located in some remote area of 
the mine. Any bias in the direction of underestimating the 
likelihood that rock will fall or underestimating the amount 
of harm it would cause increases the chances of a ground- 
fall injury because it lessens the miner's motivation to cor- 
rect the hazard. 

Miners are responsible for performing many types of ac- 
tivities and have a limited amount of time and energy with 



which to get them done. This means that whether or not 
the miner corrects a recognized hazard will depend on the 
perceived importance of performing this type of activity ver- 
sus a variety of other types of activities that the miner may 
simultaneously feel compelled to perform As mentioned 
previously, the extent to which miners are motivated to 
maintain safe work conditions is largely determined by 



management, especially the miner's immediate supervisor. 
Obviously, there is a multitude of factors that contribute 
to-the occurrence of groundfall accidents. This suggests that 
there is a multitude of approaches to the reduction of 
groundfall accidents, and that it is unlikely that any one 
approach will be a panacea. 



METHODS OF DATA COLLECTION 



A sample of miners, section supervisors, and MSHA in- 
spectors was asked to respond to a variety of questions in 
one-on-one interviews. Most of the questions were intended 
to determine if the people who work in underground coal 
mines consider the factors identified in the previous sec- 
tion to be important contributors to groundfall accidents. 
Other questions dealt with strategies for reducing the fre- 
quency of roof and rib fall accidents. 



SAMPLE 

Data were collected from February 1984 to April 1985. 
A total of 143 employees from 3 underground coal mining 
companies located at 9 sites in Pennsylvania, Virginia, and 
Kentucky participated in the study. The three companies 
are referred to here as companies A, B, and C. 

Company A owns two medium-size mines in south- 
western Pennsylvania; data were collected from 52 
employees at 1 of these 2 mines. Company B owns several 
small mines in western Virginia; data were collected from 
44 employees at 4 of these mines. Company C owns several 
small mines in western Virginia and eastern Kentucky; 
data were collected from 47 employees at 4 of these mines. 
All mines in this study were using the room-and-pillar 
method of extraction and continuous mining machinery. No 
roof fall fatalities have occurred at any of these mines. Table 
1 breaks down the total sample of mine employees by job 
title. The average length of time spent working as an 
underground coal miner was 10.5 yr. Of the 143 employees 
in the sample, 85 pet had some experience as a bolter or 
bolter helper. All 143 employees were working underground 
on a daily basis. The sample did not include cleaning plant 
personnel or other persons who work aboveground. 

Data were also collected from nine MSHA coal mine roof 
and rib inspectors. The number of years these individuals 
had been inspecting mines primarily for roof and rib con- 
trol ranged from 3 to 10 yr, with the average being 6.9 yr. 
Each of the inspectors had a sizable amount of underground 



experience, both as miners and as Federal coal mine inspec- 
tors. These participants averaged 20.1 yr of underground 
experience before they became inspectors. 

Table 1.— Breakdown of mine employees interviewed, 
by job title 

Number 

Belt worker 2 

Bridge worker 2 

Continuous miner operator 16 

Continuous miner operator helper 10 

General inside laborer 10 

Mechanic 1 1 

Roof bolter 27 

Roof bolter helper 10 

Scoop operator 2 

Section supervisor 14 

Shuttlecar operator 25 

Supply worker 2 

Timber worker 5 

Utility worker 5 

Total 143 



INTERVIEWS 

Data were collected using a structured interview guide. 
(See appendix.) Interviewers asked questions concerning the 
following issues: (1) recent experiences with roof falls, 
(2) why miners sometimes fail to do anything about poten- 
tial roof hazards, (3) why miners sometimes walk beneath 
unsupported roof, and (4) the degree to which various 
changes would help miners avoid rock fall injuries. Par- 
ticipants were asked to respond to both open-ended and 
forced-choice questions. 

All interviews with miners were conducted in private 
either at the miner's worksite or at a nearby company train- 
ing facility. Interviews with MSHA inspectors were con- 
ducted at their offices. All participants were assured that 
their responses would be held in confidence and were told 
that their participation was completely voluntary. Inter- 
views required approximately 30 min to complete. 



FINDINGS 



This section presents participants' responses to all in- 
terview questions in the sections of the interview guide (ap- 
pendix) titled "Nonresponse to Possible Roof Hazards," 
"Working Beneath Unsupported Roof," and "Techniques 
for Reducing Roof Fall Accidents." Responses to both open- 
ended and forced-choice questions are presented. For the 
forced-choice questions, simple frequencies of the response 
categories chosen to answer each question are given in 
tabular form. In these tabular listings, separate response 
distributions are given for (1) section supervisors, (2) bolters 
and bolter helpers, (3) MSHA inspectors, and (4) the total 



sample of underground miners (including the section super- 
visors, but not the MSHA inspectors). 

Because the numbers of individuals in the subgroups 
tended to be small (MSHA inspectors and supervisors 
especially), differences between the responses of people in 
these subgroups should not be looked upon as a strong in- 
dication that any substantial differences exist between the 
populations represented by the subgroups. At best, such dif- 
ferences should be viewed as weak evidence that the popula- 
tions may differ. 



NONRESPONSE TO POSSIBLE ROOF HAZARDS 

Each participant was initially asked to respond to an 
open-ended question on why miners sometimes do not take 
action to correct roof hazards. This question was followed 
by eight forced-choice questions. 

Open-Ended Questions 

Participants were asked for their opinions about why 
miners sometimes neglect to correct hazardous roof condi- 
tions. The question was asked as follows: 

At one time or another, most miners have seen 
areas of the roof that look like they may not be en- 
tirely safe, but for some reason, do not do anything 
about it. What are the major reasons why miners 
sometimes fail to do anything about potential roof 
hazards? 



The miners' replies were— 

1. in a hurry (22) 4 

2. laziness (15) 

3. the area is traveled infrequently (11) 

4. too busy doing other work (10) 

5. don't want to delay production (10) 

6. careless or don't care (8) 

7. don't believe it's hazardous (7) 

8. it's not their job (7) 

9. complacency (6) 

10. "I know it's there so I'll just stay away from it" (4) 

11. tools or supplies not readily available (4) 

12. afraid of getting hurt (4) 

13. put off doing it and forget (3) 

14. lack of knowledge or experience (2) 

15. taking shortcuts (2) 

16. not important; it's just "extra work" (2) 

Inspectors gave several different types of responses to 
this question. The most common response was that miners 
do not think it is worth the time and effort required, i.e., 
they are insufficiently motivated to correct roof hazards. 

Another reason frequently mentioned by mine inspec- 
tors was that miners do not realize how dangerous the 
hazard really is. Several inspectors also said that, because 
nothing usually happens to miners who occasionally decide 
to risk working beneath hazardous roof, many tend to 
become complacent. Apparently, the failure to experience 
negative consequences for deviating from a safe work prac- 
tice may promote continued deviation. Other factors 
believed by mine inspectors to contribute to miners' failure 
to correct roof hazards were (1) inattentiveness caused by 
preoccupation with off-the-job problems (e.g., family, 
medical) and (2) the temptation to let the next shift deal 
with the hazards when it is close to quitting time. 

Forced-Choice Questions 

Participants were asked to indicate the extent to which 
they agreed or disagreed that various reasons given by the 
interviewer explain why miners might sometimes decide 
not to do anything about potentially hazardous roof condi- 
tions. A six-point rating scale ranging from "strongly agree" 



to "strongly disagree" was used. The rating scale contained 
the following options: 

1. strongly agree 

2. agree 

3. slightly agree 

4. slightly disagree 

5. disagree 

6. strongly disagree 

The number of participants in each subgroup who chose 
each of these points on the rating scale is presented in 
tabular form for each question asked. The percentage of par- 
ticipants in each subgroup who chose either "slightly 
agree," "agree," or "strongly agree" is shown in each table 
(as "Total 'agree' responses") to allow quick understanding 
of the general results without additional calculations. (The 
numbers used in the text of this report to identify the in- 
terview questions and statements (reasons) do not corre- 
spond to the numbers used in the appendix, but the ques- 
tions and statements are the same.) 

Reason A.l: One of the main reasons miners 
sometimes neglect to correct roof hazards is 
that they don't have the tools or materials with 
them that are needed to correct the roof 
problem. 



Summary of responses: 

D „ in „ Section 
Hatmg supervisors 

Strongly agree 

Agree 7 

Slightly agree 

Slightly disagree 1 

Disagree 4 

Strongly disagree .... 2 

Total "agree" 
responses pet.. 50.0 

1 Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



6 


1 


7.1 


8 


1 


32.6 


3 


3 


11.3 


3 


2 


7.8 


4 


2 


32.6 


3 





8.5 



45.9 



55.6 



51.0 



'Numbers in parentheses indicate the number of persons who replied as 
indicated. 



Opinions about this statement were almost evenly split 
between agreement and disagreement. The data suggest 
that for many coal miners, an absence of tools and materials 
needed to fix the roof is a significant barrier to the correc- 
tion of roof hazards. However, since about half of the peo- 
ple in each work category expressed some level of disagree- 
ment, this factor cannot be considered a universal problem. 
Still, the reasons for the absence of tools and materials for 
correcting roof hazards should be further explored. 

Reason A.2: One of the main reasons miners 
sometimes neglect to correct roof hazards is 
that they think it is someone else's respon- 
sibility to take care of roof problems. 



Summary of responses: 

oo»;.,„ Section 
Hatm 9 supervisors 

Strongly agree 3 

Agree 4 

Slightly agree 4 

Slightly disagree 1 

Disagree 2 

Strongly disagree .... 

Total "agree" 
responses pet.. 78.6 

1 Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



5 


2 


9.2 


1 


2 


32.4 


3 


1 


9.9 


2 


1 


10.6 


4 


3 


31.7 


2 





6.3 



51.4 



55.6 



51.5 



Opinions about this statement were again almost evenly 
divided between agreement and disagreement. However, 
supervisors leaned more heavily toward agreement than 
disagreement. Only three of 14 supervisors expressed any 
disagreement, and three said they strongly agreed with this 
statement. These data suggest that a misperception of 
freedom from responsibility for taking care of roof problems 
is a significant deterrent to the correction of roof hazards. 
This suggests that it is important for supervisors and 
trainers to strongly emphasize that the identification and 
correction of hazardous roof conditions is the personal 
responsibility of all people who work in the mine. 



Summary of responses: 

„„,:„„ Section 
Matm 9 supervisors 

Strongly agree 2 

Agree 3 

Slightly agree 4 

Slightly disagree ..... 

Disagree 5 

Strongly disagree 

Total "agree" 
responses pet . . 64.3 

^oes not include MSHA inspectors. 



Roof 

bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



5 


1 


8.1 


6 


4 


31.1 


6 





18.5 


2 


1 


5.2 


14 


3 


33.3 


2 





3.7 



48.6 



55.6 



57.7 



Reason A.3: One of the main reasons miners 
sometimes neglect to correct roof hazards is 
because they don't want to risk getting hurt 
while fixing the roof. 

Summary of responses: 

R .. Section Roof MSHA All miners, 1 

hating supervisors bolters inspectors pet of total 

Strongly agree 2 5.0 

Agree 4 5 3 25.0 

Slightly agree 3 3 17.9 

Slightly disagree 6 6.4 

Disagree 7 17 5 40.0 

Strongly disagree .... 4 5.7 

Total "agree" 
responses pet.. 50.0 27.0 37.5 47.9 

1 Does not include MSHA inspectors. 

Again, responses were about evenly split between agree- 
ment and disagreement. However, fewer people agreed with 
this statement than with the two preceding statements. This 
was especially true among roof bolters. Because bolters 
work with the roof every day, they become accustomed to 
dealing with roof problems, and may be less fearful of be- 
ing harmed by the roof than persons who do not routinely 
work with the roof. The data suggest that fear of getting 
hurt while fixing the roof is sometimes a deterrent to the 
correction of roof hazards. It may be possible to overcome 
certain types of fears by improving the miners' ability to 
cope with potentially dangerous situations and explaining 
why certain types of fears are not valid. Valid fears should 
be dealt with by making modifications to the work environ- 
ment, better training, or withdrawing the person from the 
dangerous condition. 

Data from MSHA's accident records suggest that there 
are valid reasons why miners might fear they will be hurt 
while attempting to fix the roof. Scaling loose rock is one 
of the most common activities associated with rock fall in- 
juries. From 1980-84, 8 pet of all coal miners injured by rock 
falls were attempting to bar down loose rock from the roof 
or rib at the time they were hurt. This suggests that im- 
provements such as better training or increased compliance 
with standard operating procedures are needed, and that 
fear of harm may be a significant deterrent to the correc- 
tion of roof hazards. 

Reason A.4: One of the main reasons miners 
sometimes neglect to correct roof hazards is 
because they dislike doing the type of work 
necessary to correct the roof problem. 



The total sample of miners was split almost evenly be- 
tween agreement and disagreement. Supervisors leaned 
more heavily toward agreement than disagreement, while 
bolters exhibited the opposite tendency. One might expect 
bolters to be more likely to disagree with this statement, 
given that the correction of roof problems is a major focus 
of their job. The responses suggest that a dislike of the work 
involved in correcting roof problems is sometimes a deter- 
rent to the correction of roof hazards. The sources of dislike 
for this type of work should be explored further, and if pos- 
sible, changes should be made that would make the task 
of correcting roof problems less onerous. 

Reason A.5: One of the main reasons miners 
sometimes neglect to correct roof hazards is 
that they believe their supervisor thinks tak- 
ing care of roof problems is unimportant. 



Summary of responses: 

_ . Section 

" atin 9 supervisors 

Strongly agree 

Agree 

Slightly agree 1 

Slightly disagree 

Disagree 8 

Strongly disagree .... 5 

Total "agree" 
responses pet. 7.1 

^oes not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 









0.7 


2 





7.8 





1 


2.8 





1 


2.8 


21 


6 


56.7 


14 


1 


29.1 



5.4 



11.1 



11.3 



There was very little agreement with this statement. 
Only 1 1 pet of the total sample of miners expressed agree- 
ment with this statement. This data suggests that super- 
visors' disinterest in correcting roof problems is not a signifi- 
cant barrier to the prevention of groundfall accidents. Given 
the importance of their role in maintaining the safety of 
mining crews, any evidence of a supervisor's disinterest in 
the correction of roof problems should be thoroughly 
explored. 

Reason A.6: One of the main reasons miners 
sometimes neglect to correct roof hazards is 
because they don't know how to correct roof 
problems. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



1 


1 


2.9 


4 


1 


20.7 


3 


1 


12.9 


3 


1 


5.7 


22 


4 


45.7 


4 





12.1 



21.6 



37.5 



36.5 



Summary of responses: 

R . Section 

Mating supervisors 

Strongly agree 1 

Agree 5 

Slightly agree 3 

Slightly disagree 1 

Disagree 2 

Strongly disagree .... 2 

Total "agree" 
responses pet . . 64.3 

1 Does not include MSHA inspectors. 



As one might expect, few bolters expressed agreement 
with this statement. However, about 37 pet of the overall 
sample expressed agreement with this statement. This sug- 
gests that a lack of knowledge about the correction of roof 
problems is sometimes a deterrent to the correction of roof 
hazards. Efforts should be made to identify the most effec- 
tive methods for training miners to correct roof fall problems 
and to ensure that all persons working underground under- 
stand how to correct roof problems. 

Reason A.7: One of the main reasons miners 
sometimes neglect to correct roof hazards is 
that they don't realize how dangerous roof 
problems are. 



Summary of responses: 

Do.;„„ Section 

Hatln 9 supervisors 

Strongly agree .:.... 3 

Agree 6 

Slightly agree 

Slightly disagree 1 

Disagree 3 

Strongly disagree .... 1 

Total "agree" 
responses pet . . 64.3 

1 Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



8 


2 


13.7 


4 


5 


43.2 


7 


2 


11.5 








2.9 


6 





20.9 


2 





7.9 



78.4 



100.0 



68.4 



There was a high level of agreement with this statement 
across all categories of persons who work underground. It 
appears there may be a tendency for miners to under- 
estimate the level of danger associated with roof problems. 
Therefore, efforts should be made to impress upon them the 
magnitude of the damage that uncorrected roof problems 
can cause to people and equipment. 

Reason A.8: One of the main reasons miners 
sometimes neglect to correct roof hazards is 
that they don't take enough time to look for 
roof problems. 



Summary of responses: 

n „ ti __ Section 

i-iaung supervisors 

Strongly agree 3 

Agree 6 

Slightly agree 4 

Slightly disagree 1 

Disagree 

Strongly disagree .... 

Total "agree" 
responses pet . . 93.0 

''Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



7 


3 


11.4 


14 


4 


55.0 


6 


1 


14.3 


2 





5.0 


8 





14.3 








0.0 



73.0 



100.0 



80^ 



There was a high level of agreement with this statement 
across all categories of persons. Eighty-one percent of the 
total sample agreed with this statement. The data suggest 
that a major deterrent to the prevention of groundfall ac- 
cidents is that miners devote too little time to the visual 
inspection of the roof and rib. Attention should be given 
to understanding what could be done to motivate miners 
to spend more time looking for hazardous roof conditions. 

Table 2 rank-orders the above eight reasons in terms 
of the highest (rank 1) to the lowest (rank 8) percentage of 
persons who responded that they strongly agreed, agreed, 
or slightly agreed. With the exception of reason A.5, a 
significant number of miners agreed that each of the fac- 
tors listed in this section is an important deterrent to the 
prevention of groundfall accidents. This suggests that fur- 
ther attention should be given to devising better ways to 
lessen the influence of these seven barriers. 



Table 2.— Rank ordering of reasons for neglect of roof fall 

hazards according to percentage of persons 

expressing agreement 1 

R All Section Roof MSHA 
Heason miners 2 supervisors bolters inspectors 

A.8. They don't take enough 
time to look for roof 
problems 1 1 2 1-2 

A.7. They don't realize how 

dangerous roof problems 

are 2 3-5 1 1-2 

A.4. They dislike doing the type 
of work necessary to cor- 
rect the problem 3 3-5 4 4-5 

A.2. They think it is someone 

else's responsibility 4 2 3 3 

A.1 . They don't have the tools 
or materials to correct 
the problem 5 6-7 5 4-5 

A. 3. They don't want to risk get- 
ting hurt 6 6-7 6 6-7 

A. 6. They don't know how to 

correct the roof problem .7 3-5 7 6-7 

A.5. They believe their super- 
visor thinks that taking 
care of roof problems is 

unimportant 8 8 8 8 

1 "Agreement" here includes "strongly agree," "agree," and "slightly agree" 

responses. Ranking of 1 indicates highest percentage of responses in agree- 
ment; 8 indicates least agreement. 
2 Does not include MSHA inspectors. 



WHY MINERS SOMETIMES WALK BENEATH 
UNSUPPORTED ROOF 

The victims of roof falls are often found in areas of un- 
supported roof. MSHA fatality reports indicate that more 
than half of the 97 deaths due to groundfalls in coal mines 
during 1979 and 1980 occurred in areas of unsupported roof. 
The open-ended and forced-choice questions that follow were 
directed toward better defining the reasons why miners fail 
to avoid unsupported roof. 

Open-Ended Questions 

MSHA roof and rib inspectors were asked what moti- 
vates miners to illegally go beneath unsupported roof. (The 
only legally permissible reason for going beneath unsup- 
ported roof is to set temporary supports before installing 
permanent supports.) The most common reply to this ques- 
tion was that miners do it to save time and/or effort, i.e., 
they want to take a shortcut. 

Inspectors mentioned several factors that sometimes 
contribute to miners' willingness to risk working beneath 
unsupported roof. Among them were the following: 



4. 
5. 
6. 

7. 



1. They are in a hurry to get more coal out, especially 
if they think they are behind in production. 

2. They want to cut down the walking distance to a 
place they need to go. 

3. They think the unsupported roof "looks good" (safe). 
They do it inadvertently. 

They have done it before without getting hurt. 
They are unwilling to set temporary supports. 
In order to finish loading a shuttle car, continuous 

miner operators might go a little beyond the edge of prop- 
erly supported roof. 

Forced-Choice Questions 

In this section of the interview, participants were asked 
forced-choice questions about (1) reasons for walking under 
unsupported roof, (2) whether miners inspect unsupported 
roof before walking under it, and (3) the proportion and fre- 
quency of miners who walk beneath unsupported roof. 



Reasons for Walking Under Unsupported Roof 

Participants were asked to indicate the extent to which 
they agreed or disagreed that various reasons given by the 
interviewer explain why miners sometimes walk beneath 
unsupported roof. Participants again used a six-point rating 
scale to respond to each statement ("strongly agree," 
"agree," etc.). Each reason was prefaced by, "One of the 
main reasons miners sometimes walk beneath unsupported 
roof is that ..." The participants' responses to these 
statements are presented in the same manner as those in 
the preceding section on nonresponse to possible roof 
hazards. 

Reason B.l: One of the main reasons miners 
sometimes walk beneath unsupported roof is 
that they do not realize they have gone beyond 
the edge of roof that is properly supported and 
do not intend to do so. 



Summary of responses: 

n„ in „ Section 
Halln 9 supervisors 

Strongly agree 

Agree 8 

Slightly agree 1 

Slightly disagree 1 

Disagree 3 

Strongly disagree .... 1 

Total "agree" 

responses pet . . 64.3 

'Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



3 





8.5 


10 


2 


44.7 


9 


5 


12.8 


1 





2.8 


10 


2 


24.8 


3 





6.4 



61.1 



77.8 



66.0 



Sixty-six percent of the sample expressed some level of 
agreement with this statement. Several participants in- 
dicated that their answer to this statement would vary 
depending on the mine's seam height, i.e., it is more dif- 
ficult to inspect the roof when crawling or stoopwalking 
than when walking upright. 

Reason B.2: One of the main reasons miners 
sometimes walk beneath unsupported roof is 
that they do not believe it is unsafe to do so. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



1 


3 


2.9 


12 


5 


33.8 


5 





12.9 


1 





2.9 


14 


1 


38.1 


2 





9.4 



51.4 



88.9 



49.6 



Summary of responses: 

o„.i„„ Section 
Hatln 9 supervisors 

Strongly agree 1 

Agree 5 

Slightly agree 3 

Slightly disagree 

Disagree 5 

Strongly disagree .... 

Total "agree" 
responses pet . . 64.3 

^oes not include MSHA inspectors. 



Miners' opinions about this statement were about 
evenly split between agreement and disagreement. How- 
ever, supervisors and mine inspectors leaned more heavily 
toward agreement. All but one of nine inspectors agreed 
or strongly agreed with this statement. 

It is not hard to understand why some miners might 
become convinced that unsupported roof is safe. First, there 
is often no way miners can anticipate when unsupported 
roof is going to collapse. Except for the absence of supports, 
unsupported roof may look entirely safe. In most mines, roof 
falls leading to serious injury are not a common occurrence, 
and miners can often go beneath unsupported roof without 
being injured. The more times a miner goes beneath un- 
supported roof without being injured, the more convinced 
he or she will be that unsupported roof is not dangerous. 
Although roof falls are not an everyday event, they all too 
often produce disastrous consequences when they occur. It 
is particularly important to keep new miners from form- 
ing the habit of going beneath unsupported roof, because 
habits are difficult to break. 

Reason B.3: One of the main reasons miners 
sometimes walk beneath unsupported roof is 
that they are trying to save time. 



Summary of responses: 

_ . Section 

Mating supervisors 

Strongly agree . 

Agree 8 

Slightly agree 3 

Slightly disagree 1 

Disagree 2 

Strongly disagree .... 

Total "agree" 
responses pet . . 78 6 

'Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners.' 
pet of total 



5 


C 


8.6 


20 


7 


58.6 


6 


1 


11.4 


2 





5.0 


3 


1 


150 








2.0 



86.1 



889 



78.6 



There was a high level of agreement with this statement 
across all categories of participants. It would be useful to 
understand the types of circumstances most likely to cause 
miners to take dangerous shortcuts in order to save time. 
Because the activities of mining coal and roof bolting are 
somewhat interdependent, significant delays in roof bolting 
might motivate bolters to take dangerous shortcuts in order 
to catch up with the rest of the cycle of mining activities 
in their section. 

Therefore, mine operators should be especially con- 
cerned with planning for and dealing with unplanned 
events that could delay roof bolting activities. It might be 
possible to prevent such delays through modification of work 
precedures or equipment. 



Reason B.4: One of the main reasons miners 
sometimes walk beneath unsupported roof is 
that it takes too much effort to set temporary 
supports. 



Summary of responses: 

□-,.;„„ Section 
Hatin 9 supervisors 

Strongly agree 1 

Agree 7 

Slightly agree 2 

Slightly disagree 

Disagree 4 

Strongly disagree .... 

Total "agree" 
responses pet . . 71 .4 

'Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



2 


2 


8.8 


11 


2 


37.5 


5 


2 


13.2 


1 


1 


1.5 


9 


2 


30.9 


7 





8.1 



51.4 



66.7 



59.5 



The majority of each category of participant expressed 
agreement with this statement. This suggests that con- 
sideration should be given to redesigning the equipment 
and procedures associated with setting temporary roof sup- 
ports. The Bureau of Mines recently developed a new roof 
jack that is lighter in weight and easier to carry than 
previous roof jacks. Any improvements that would make 
the task of temporary roof support easier would help miners 
to overcome this barrier to the prevention of groundfall 
accidents. 

Reason B.5: One of the main reasons miners 
sometimes walk beneath unsupported roof is 
that they have often seen other people do it. 



Summary of responses: 

ootir.^ Section 
Hating supervisors 

Strongly agree 1 

Agree 8 

Slightly agree 2 

Slightly disagree 

Disagree 2 

Strongly disagree .... 

Total "agree" 
responses pet.. 84.6 

'Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



8 





10.9 


4 


5 


51.4 


2 


1 


9.4 


2 


2 


2.2 


8 


1 


22.5 


2 





3.6 



66.7 



66.7 



71.7 



There was a high level of agreement with this statement 
across all categories of participants. This suggests that 
walking beneath unsupported roof may be analogous to a 
contagious disease. It not only poses a threat to the well- 
being of the individual who is beneath the unsupported roof, 
it is also likely to spread to others in the vicinity. Observ- 
ing that no harm comes to coworkers who walk beneath un- 
supported roof causes others to be less cautious. Walking 
beneath unsupported roof could become commonplace 
among members of a mining crew. In such crews, the peer 
group pressure to engage in this dangerous practice might 
be very difficult to overcome. 

Miners' responses to this question suggest that walk- 
ing beneath unsupported roof is a potentially contagious 
behavior. Therefore, it is important that such behavior be 
quickly eliminated, because if it is tolerated, it is likely to 
spread among the work force. 

Table 3 rank-orders the first five statements in terms 
of the highest (rank 1) to the lowest (rank 5) percentage of 
persons who responded that they strongly agreed, agreed, 
or slightly agreed. At least half of the total miners group 



Table 3.— Rank ordering of reasons why miners go beneath 

unsupported roof according to percentage of 

persons expressing agreement 1 

„ All Section Roof MSHA 

" eason miners 2 supervisors bolters inspectors 

B.3. They are trying to save 

some time 1 2 1 1-2 

B.5. They have often seen other 

people do it 2 1 2 4-5 

B.1. They do not realize they 

have gone beyond the 

edge of roof that is pro- 
perly supported, and did 

not intend to do so 3 4-5 3 3 

B.4. It takes too much time to 

set temporary supports . . 4 3 4-5 4-5 

B.2. They do not believe it is 

unsafe to do so 5 4-5 4-5 1-2 

'"Agreement" here includes "strongly agree," "agree," and "slightly agree" 
responses. Ranking of 1 indicates highest percentage of responses in agree- 
ment; 5 indicates least agreement. 
2 Does not include MSHA inspectors. 

expressed agreement with all five statements. This suggests 
that (1) all of the reasons listed in this section were con- 
sidered to be important reasons why miners sometimes go 
beneath unsupported roof by a substantial number of par- 
ticipants and (2) that attention should be given to devising 
effective methods for counteracting these reasons. 

Precautionary Behavior 

In order to roughly estimate whether most miners stop 
to visually inspect unsupported roof before walking beneath 
it, miners were asked if they agreed or disagreed with the 
following statement: 

Statement B.6: Most miners do not walk be- 
neath unsupported roof before looking at it 
carefully. 



Summary of responses: 

„„.:„„ Section 

Hatl "9 supervisors 

Strongly agree 

Agree 8 

Slightly agree 3 

Slightly disagree 2 

Disagree 1 

Strongly disagree .... 

Total "agree" 
responses pet . . 78.6 

'Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



5 





6.6 


22 


3 


68.4 


3 


2 


12.5 


2 


3 


3.7 


3 


1 


7.4 


1 





1.5 



83.3 



55.6 



87.5 



A substantial majority of all three categories of mine 
employees expressed agreement with this statement. This 
suggests that miners who walk beneath unsupported roof 
are somewhat fearful of being struck by a roof fall, and at 
least stop to visually inspect the roof before proceeding out 
beyond the edge of supported roof. 



Proportion and Frequency of Miners 
Walking Beneath Unsupported Roof 

In order to roughly estimate the proportion of miners 
who go beneath unsupported roof, miners were asked, "Dur- 
ing a typical month, what percentage of miners who work 
at the face go beneath unsupported roof for reasons other 
than to set temporary supports?" Miners' responses to this 
question are given in table 4. The median of the estimates 
for the percentage of miners who go beneath unsupported 



10 



roof during a typical month was 10 pet. (Half of the 
estimates were greater than 10 pet and half the estimates 
were less than 10 pet.) This suggests that the percentage 
of miners who go beneath unsupported roof is relatively low. 
In order to estimate the frequency with which miners 
go beneath unsupported roof, miners were asked, "Consider- 
ing a typical crew of miners who work at the face, how often 
does someone go beneath unsupported roof for reasons other 
than to set temporary supports?" Miners' responses to this 
question are listed in table 5. Approximately 44 pet of the 
miners indicated that they believe someone goes beneath 
unsupported roof at least once per shift. 

Table 4. — Estimates of percentage of miners who go 
beneath unsupported roof during a typical month 



Estimate, 
pet 



Miners 
in agreement 
with estimate 



Miners 

in agreement 

with estimate, 

pet 





1 

2 

5 

9 

10 

15 

20 

25 

30 

35 

50 

60 

75 

80 

90 

100 

Total 



34 
9 
8 
9 
1 

21 
2 
7 
7 
4 
2 

13 
1 
2 
2 
2 
1 



27.2 

7.2 

6.4 

7.2 

.8 

16.8 
1.6 
5.6 
5.6 
3.2 
1.6 

10.4 

.8 

1.6 

1.6 

1.6 

.8 



125 



100.0 



taken to prevent groundfali accidents. This question was 
followed by nine forced-choice questions. 



Open-Ended Questions 

Miners were asked for their opinions about what should 
be done to reduce the number of rock fall accidents in the 
coal industry. Their replies were— 

1. better training (19) 5 

2. inspect the roof more often (14) 

3. don't make entries too wide (7) 

4. drill test holes more frequently and/or deeper (7) 

5. always set temporary supports before walking 
beyond bolts (7) 

6. put more emphasis on the dangerousness of ground- 
fall accidents (7) 

7. follow the roof control plan and/or bolting pattern 
more closely (6) 

8. use more automated temporary roof support (ATRS) 
type bolters (5) s 

9. recheck existing supports more often (5) 

10. add more supports to bad areas (5) 

11. stricter supervision (4) 

12. use more bolts (4) 

13. use longer bolts (4) 

14. don't rush (4) 

15. put less emphasis on production (3) 

16. scale the roof better (2) 

17. check the torque on roof bolts more often (2) 

18. sound the roof more often (2) 

19. more safety talks (2) 



Table 5.— Estimates of frequency with which someone in a 
typical crew of miners goes beneath unsupported roof 



Estimate, 
pet 



Miners 
in agreement 
with estimate 



Miners 

in agreement 

with estimate, 

pet 



At least once per shift . . 


48 


At least once per week, 




but less often than 




once every shift 


28 


At least once per month, 




but less often than 




once every week .... 


16 


Less than once per 




month 


18 


Total 


110 



43.6 

25.4 

14.6 
16.4 



100.0 



Over 25 pet indicated that they believed someone goes 
beneath unsupported roof at least once per week but not 
as often as once per shift. These estimates suggest that go- 
ing beneath unsupported roof is not an uncommon event 
in a typical mining crew, and, that more attention should 
be given to preventing miners from engaging in this prac- 
tice. In conjunction with the data from table 4, these 
estimates suggest that few miners go beneath unsupported 
roof, but that those who do, do it rather often. 

OPINIONS ON VARIOUS MEASURES FOR 
PREVENTING GROUNDFALL ACCIDENTS 

Each participant was initially asked to respond to an 
open-ended question concerning measures that could be 



Other responses included the following: put canopies on roof 
bolters, operate equipment by remote control, offer bonuses 
for good roof support, install roof supports more quickly after 
the area is mined, install bolts closer to the rib, encourage 
communication between miners about the existence of new 
roof problems, and explain some of the theoretical principles 
behind roof support. 

MSHA inspectors were also asked what they thought 
needs to be done to prevent more roof fall accidents in the 
coal industry. The most common response was that the use 
of ATRS systems on bolters should be mandatory. Such 
systems are expected to significantly reduce the amount of 
time miners spend beneath unsupported roof. Other 
responses included: 

1. Use remote sensing devices to check for gas at the 
face. 

2. Do not assign inexperienced crews to perform retreat 
mining. 

3. Encourage continuous miner operators to report roof 
problems to bolters. 

4. Avoid letting sections stand idle during pillar 
recovery. 



'Numbers in parentheses indicate the number of persons who replied as 
indicated. 

'Unsupported coal mine roof must be temporarily supported (usually with 
jacks) before permanent supports (usually bolts) are installed. Without the 
ATRS system, bolters must expose themselves to unsupported roof in order 
to set the temporary supports. Bolting machines equipped with ATRS sup- 
port the roof with hydraulic jacks mounted at the front of the machine while 
roof bolts are being installed. This eliminates the need for miners to expose 
themselves to unsupported roof while temporary supports are set. 



11 



5. Ensure closer compliance with the roof control plan 
and safety rules. 

6. Improve training. 

With regard to the improvement of training, inspectors 
recommended the following: 



(However, this may not always be feasible.) Another bar- 
rier to the recognition of such indexes of dangerous roof and 
rib rock is poor eyesight. Periodic vision tests would help 
to ensure that miners can see well. Good vision is especially 
important for those who work in areas where hazardous roof 
conditions are likely to exist. 



1. Supplement classroom training with structured on- 
the-job training in roof control and identification of ground- 
fall hazards. 

2. Explain the theory behind current methods of roof 
support to bolters in lay terms. 

3. Limit the size of training classes to encourage more 
discussion. 

4. Increase miners' awareness of the consequences of 
roof falls by showing slides of roof fall accidents and relating 
the details of how people have been injured by them. 

Forced-Choice Questions 

Participants were asked to indicate the degree to which 
various changes would help miners avoid rock fall injuries. 
A six-point rating scale ranging from "a very small degree" 
to "a very large degree" was used to respond to each state- 
ment. The rating scale contained the following options: 

1. a very small degree 

2. a small degree 

3. a somewhat small degree 

4. a somewhat large degree 

5. a large degree 

6. a very large degree 

Nine different changes (environmental, procedural, etc.) 
were inserted into the blank in the following question: To 

what degree would help miners avoid rock 

fall injuries? The number of participants in each subgroup 
who chose each point on the rating scale is presented below. 
The last row of numbers indicates the percentage of par- 
ticipants in each subgroup who either chose "a large 
degree" or "a very large degree" to answer the question. 
These percentages allow quick understanding of the general 
results without any additional calculations. 



Question C.l: To what degree would better 
lighting help miners avoid rock fall injuries? 



Summary of responses: 

D „i„„ Section 
Hating supervisors 

Very small 3 

Small 3 

Somewhat small 1 

Somewhat large 2 

Large 3 

Very large 1 

Large or very 
large pet 30.8 

1 Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



3 


1 


14.2 


11 


2 


26.9 


3 


2 


9.7 


2 


2 


5.2 


8 


2 


30.6 


5 





13.4 



40.6 



22.2 



44.0 



Forty-four percent of the mine employees said better 
lighting would help miners avoid rock fall injuries to a large 
or very large degree. Indexes of dangerous roof conditions 
such as cracks and gaps in the rock would probably be 
noticed more readily if mine roofs were better illuminated. 



Roof 
bolters 



MSHA 
inspectors 



All miners,' 
pet of total 



Question C.2: To what degree would less 
noise help miners avoid rock fall injuries? 



Summary of responses: 

o-,.;„„ Section 

Hatln 9 supervisors 

Very small 2 

Small 1 

Somewhat small 2 

Somewhat large 1 

Large 6 

Very large 2 

Large or very 
large pet 57.2 

1 Does not include MSHA inspectors. 



4 





7.5 


9 


2 


19.4 





2 


6.0 


2 


1 


11.2 


12 


3 


38.1 


5 


1 


17.9 



53.1 



44.4 



56.0 



Fifty -six percent of the mine employees said less noise 
would be a large or very large help. Indexes of dangerous 
roof conditions such as cracking and pinging sounds and 
small pieces of rock falling to the floor sometimes warn 
miners that a roof fall is imminent. However, such sounds 
are likely to go unnoticed if noisy equipment is operating 
in the vicinity. Therefore, efforts should be made to keep 
face areas as free from noise as possible. 

Question C.3: To what degree would super- 
visors putting greater emphasis on correcting 
roof hazards help miners avoid rock fall 
injuries? 



Summary of responses: 

„,,!„„ Section 
Hatin 9 supervisors 

Very small 1 

Small 1 

Somewhat small 

Somewhat large 2 

Large 7 

Very large 3 

Large or very 
large pet 71 .4 

'Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners,' 
pet of total 



4 





6.7 


6 





15.6 


3 





4.4 


4 


2 


17.0 


10 


4 


37.8 


5 


3 


18.5 



46.9 



77.8 



56.3 



Fifty-six percent of the mine employees said that super- 
visors putting greater emphasis on correcting roof hazards 
would be a large or very large help. The percentage of super- 
visors who chose these two response categories (71.4 pet) 
was higher than the corresponding percentage for all miners 
(56.3 pet), and the corresponding percentage for inspectors 
was even higher (77.8 pet). Section supervisors play a critical 
role in maintaining their crews' safety. It is essential that 
supervisors do a good job of emphasizing the maintenance 
of safe roof conditions. It may be necessary to help super- 
visors who are not effective at this aspect of their job by 
providing them with additional training on supervisory 
skills and/or ground control. 

. 
Question C.4: To what degree would better 
training in the identification of roof hazards 
help miners avoid rock fall injuries? 



12 



Summary of responses: 

Rating supervisors 

Very small 1 

Small 2 

Somewhat small 1 

Somewhat large 2 

Large 3 

Very large 5 

Large or very 
large pet 57.1 

^oes not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



1 





3.0 


2 


1 


6.0 


3 





6.8 


3 


4 


15.8 


15 


2 


45.1 


6 


2 


23.3 



70.0 



44.4 



68.4 



Sixty -eight percent of the mine employees said better 
training in the identification of roof hazards would help 
miners avoid rock fall injuries to a large or very large 
degree. This suggests that an important barrier to miners' 
prevention of groundfall accidents is that miners are unable 
to recognize certain types of roof conditions as hazardous. 
(The Bureau is helping to alleviate this problem by develop- 
ing a comprehensive set of stereoscopic slides of groundfall 
hazards than can be used to illustrate these hazards and 
show miners how to correct them. Stereoscopic slides pro- 
vide a much more realistic representation of groundfall 
hazards than can be achieved through conventional slides.) 

MSHA inspectors were asked to list the types of cues 
that can warn miners that a piece or an area of the roof 
is about to fall. They were then asked to choose which of 
these warning signals would be most difficult for inex- 
perienced miners to recognize as indicators of danger. The 
following visual cues were mentioned: 

1. cracked, bent, or broken support posts 

2. cracks, gaps, slips, cutters, and clay veins in the roof 
and rib 

3. heaving of the floor 

4. loose rock lying on the floor 

5. the absence of rock dust on previously dusted 
surfaces 

6. bent plates around bolts 

7. cracked, bent, broken, or squeezed cap blocks, cross- 
bars, or cribs 

8. sags in the middle of the roof or crossbars 

9. reduction in clearance between tops of equipment 
and the roof over time 

10. dust trickling down from the roof 

11. water seeping out of roof bolt holes 

12. kettlebottoms and ether fossils 

The following auditory cues were mentioned: 

1. sounds associated with "sounding the roof 

2. noise caused by shifts in the stress distribution on 
various layers of rock, i.e., when the roof is "working" 

3. cracking of wooden supports due to stress 
concentrations 

4. pinging noises from roof bolts caused by increased 
roof loading 

It was noted that roof bolters receive several types of cues 
about the stability of the roof when drilling bolt holes. It 
was also noted that these warning signals are not univer- 
sal; they may vary with the type of coal seam and geological 
conditions. 

Responses to the question, "Which types of warning 
signals are more difficult for inexperienced miners to 
recognize (as opposed to miners with several years of ex- 
perience)?" included clay veins, cutters, sloughing of the 



ribs, cracking or heaving of the floor, the presence of sand- 
stone channels, and pinging noises produced by bolts. 

Question C.5: To what degree would better 
training in proper methods of supporting the 
roof help miners avoid rock fall injuries? 



Summary of responses: 

D,.ir,„ Section 
Hatln0 - supervisors 

Very small 1 

Small 3 

Somewhat small 

Somewhat large 2 

Large 5 

Very large 3 

Large or very 
large pet 57.1 

'Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 




5 

1 

4 

14 

7 



67.8 



55.6 



2.3 
11.3 

3.0 
14.3 
43.6 
25.6 



69.2 



Sixty-nine percent of the mine employees said better 
training in proper methods of supporting the roof would be 
a large or very large help. This suggests that miners' lack 
of knowledge concerning proper methods of roof support is 
an important barrier to the prevention of groundfall ac- 
cidents. This type of training should be conducted both in 
the classroom and underground. It is important that miners 
get hands-on experience under the close supervision of some- 
one knowledgeable in the proper methods of roof support. 

Question C.6: To what degree would repri- 
manding or penalizing those who repeatedly 
go beneath unsupported roof help miners 
avoid rock fall injuries? 



Summary of responses: 

R . Section Roof MSHA All miners. 1 

9 supervisors bolters inspectors pet of total 

Very small 1 4 10.4 

Small 2 8 1 14.8 

Somewhat small 2 2 1 5.2 

Somewhat large 1 1 9.6 

Large 5 8 4 28.9 

Very large 3 10 2 31.1 

Large or very 
large pet 57.1 56J3 66_7 60.0 

1 Does not include MSHA inspectors. 



The majority of participants in each category* said that 
reprimands or penalties would be a large or very large help. 
This suggests that section supervisors should not hesitate 
to reprimand and penalize individuals who repeatedly go 
beneath unsupported roof if other methods of convincing 
them not to do this prove ineffectual. These data suggest 
that most miners believe such actions are likely to be ef- 
fective. Again, it is important that supervisors take 
whatever actions are necessary to stop miners from going 
under unsupported roof as soon as possible— before it 
becomes habitual and commonplace. 



Question C.7: To what degree would better 
scaling of the roof help miners avoid rock fall 
injuries? 



13 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



1 





2.2 


7 


1 


17.2 


3 


1 


8.2 


5 


2 


15.7 


1 


3 


37.3 


5 





19.4 



50.0 



42.9 



56.7 



Summary of responses: 

o„.i„„ Section 

Hatm 9 supervisors 

Very small 

Small 4 

Somewhat small 2 

Somewhat large 2 

Large 4 

Very large 2 

Large or very 
large pet 42.9 

'Does not include MSHA inspectors. 



Fifty -seven percent of the mine employees said better 
scaling of the roof would help miners avoid rock falls to a 
large or very large degree. This suggests that there is often 
a need for more emphasis on keeping the roof properly 
scaled. It is important that miners realize and be reminded 
that it is necessary to take down even relatively small pieces 
of loose rock, because it does not take much rock to cause 
a serious injury or fatality. 

Question C.8: To what degree would adding 
more support to bad areas of the roof help 
miners avoid rock fall injuries? 



Summary of responses: 

□o.;„„ Section 

Hatin 9 supervisors 

Very small 1 

Small 2 

Somewhat small 1 

Somewhat large 1 

Large 5 

Very large 4 

Large or very 
large pet 64.3 

1 Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 









3.0 


2 


1 


5.3 


1 


1 


3.8 


4 


2 


9.0 


16 


4 


39.8 


9 





39.1 



78.1 



50.0 



78.9 



Seventy-nine percent of the mine employees said that 
adding more support to bad areas of the roof would be a 
large or very large help. This suggests that it is important 
to make sure the roof has not deteriorated to the point of 
being dangerous. 

Question C.9: To what degree would better in- 
stallation of roof bolts help miners avoid rock 
fall injuries? 



Summary of responses: 

D-,»:„„ Section 

Hat '"9 supervisors 

Very small 1 

Small 3 

Somewhat small 2 

Somewhat large 3 

Large 3 

Very large 2 

Large or very 
large pet 35.7 

1 Does not include MSHA inspectors. 



Roof 
bolters 



MSHA 
inspectors 



All miners, 1 
pet of total 



2 





6.1 


10 


3 


25.8 


1 


4 


5.3 


1 





9.8 


9 


2 


25.8 


8 





27.3 



54.8 



22.2 



53.1 



It is interesting that the percentage of roof bolters who 
chose either the "large" or "very large" response (54.8 pet) 
was substantially higher than the corresponding percent- 
age for supervisors (35.7 pet) and for MSHA inspectors (22.2 
pet). Because bolting is the central focus of their work, 
bolters may tend to exaggerate the importance of inade- 
quate bolting as a contributor to groundfall accidents. These 



data suggest that better bolting could help reduce the oc- 
currence of groundfall accidents. Research should be con- 
ducted to discover the types of errors commonly made by 
bolters, why these errors occur, and how they can be 
prevented. 

Table 6 rank-orders the nine questions in this section 
in terms of the highest (rank 1) to the lowest (rank 9) per- 
centage of persons who chose either the "large" or "very 
large" responses. Better lighting received the lowest rank- 
ing from all four subgroups. The ranking for less noise was 
relatively low for all of the subgroups except supervisors. 
"Supervisors putting greater emphasis on correcting roof 
hazards" was ranked highest by supervisors and MSHA in- 
spectors, but was ranked relatively low by all miners and 
roof bolters. Rankings for better training in the identifica- 
tion of roof hazards, better training in proper methods of 
supporting the roof, and reprimanding or penalizing those 
who repeatedly go beneath unsupported roof were in the 
middle range (between 2 and 6). Adding more support to 
bad areas of the roof was ranked number 1 by the total 
miners group and by roof bolters, and was ranked number 
2 by supervisors. Better installation of roof bolts ranked 
nearly last. Items C.l, C.2, C.7, C.8, and C.9 all refer to 
changing the physical work environment, whereas items 
C.3 through C.6 all refer to changes in miners' training and 
supervision. Except for item C.8, there was a consistent 
tendency across all subgroups for the percentages of par- 
ticipants in the "large" or "very large" response categories 
(with the responses referring to degree of help) to be higher 
for the proposed changes in training and supervision than 
for the proposed changes in the physical work environment. 

Except for better lighting, the majority of the total 
miners group indicated that all of the proposed changes 
would help miners avoid rock fall injuries to a large or very 
large degree. (The corresponding percentage for better 
lighting was 44 pet.) The perceived importance of the nine 
changes proposed in this section for reducing rock fall in- 
juries suggests that consideration should be given to the 
possibility of implementing all nine of them. Obviously, 
some of these changes are not as feasible as others. Their 
feasibility could be determined by several factors, including 
the cost of research and implementation and the probabil- 
ity of success. 

Table 6. — Rank ordering of responses about degree to which 

various changes would help miners avoid rock fall injuries, 

according to percentage of persons who chose "large" or 

"very large" degree response 1 

R All Section Roof MSHA 

eason miners 2 supervisors bolters inspectors 

C.8. Adding more support to 

bad areas of the roof . . 1 2 1 4 

C.5. Better training in proper 

methods of supporting 

the roof 2 4-6 3 2 

C.4. Better training in the 

identification of roof 

hazards 3 4-6 2 5-6 

C.6. Reprimanding or penaliz- 
ing those who 

repeatedly go beneath 

unsupported roof 4 4-6 4 2 

C.7. Better scaling of the roof .5 7 7 7 

C.3. Supervisors putting 

greater emphasis on 

correcting roof hazards 6 18 1 

C.2. Less noise 7 3 6 5-6 

C.9. Better installation of roof 

bolts 8 8 5 8-9 

C.1. Better lighting 9 5) 9 , 8-9 

1 Ranking of 1 indicates highest percentage of responses in "large" or 
"very large" categories; 9 indicates lowest percentage in these 
categories. 
2 Does not include MSHA inspectors. 



14 



MINERS' EXPERIENCES WITH ROCK FALLS 



The most comprehensive source of data about ground- 
falls is maintained by MSHA's Health and Safety Analysis 
Center in Denver, CO. Several breakdowns and statistics 
were generated from MSHA's records on groundfall ac- 
cidents. These data are quite informative and useful and 
are presented later in this section. However, several other 
types of potentially useful information about groundfalls 
are not available from MSHA. Therefore, the miners inter- 
viewed for this study were asked to provide information 
about their recent experiences with rock falls that is not 
typically collected by MSHA. Miners were asked for detailed 
information about either (1) recent injuries they had suf- 
fered as a result of a rock fall or (2) incidents in which they 
were startled due to their proximity to large pieces of falling 
rock. 

EXPERIENCES REPORTED BY THE MINERS IN 
THIS STUDY 

Miners were asked several questions about their ex- 
periences with rock fall accidents. (These questions are 
listed in the appendix.) The responses to these questions 
are summarized in two sections. The first section ("Injured") 
summarizes data from 31 miners who had suffered some 
type of injury caused by a rock fall during the preceding 
2 yr. The second section ("Not Injured") summarizes data 
from 57 other miners who had not been recently injured, 
but had been startled by large pieces of falling rock 
sometime during the past year. 

Injured 

Ten miners reported that they had suffered a lost-time 
injury due to a rock fall sometime during the past 2 yr. 
Twenty-one others said they had suffered an injury due to 
a rock fall without lost time sometime during the past year. 
When asked where they were when the injury occurred, 25 
of these 31 miners said they were within approximately 
25 ft of the face. When asked how long they had been near 
the location of the rock fall before the fall actually occurred, 
20 of these 31 miners reported that they had been there for 
only a few minutes prior to the accident. The activities be- 
ing performed at the time of the accident were— 

1. roof bolting (15) 7 

2. setting temporary supports (4) 

3. standing or walking (3) 

4. operating a continuous miner (3) 

5. operating a shuttle car (2) 

6. shoveling (1) 

7. putting up a brattice (1) 

8. eating dinner (1) 

9. sawing a timber (1) 

Not Injured 

Of the 119 persons who had not recently been injured 
by a rock fall, 57 said they had been startled by large pieces 
of falling rock sometime during the past year. Of these 57 
individuals, 46 reported that such an incident had happened 
more than once within the past year. The median number 

'Numbers in parentheses indicate the number of persons who replied as 
indicated. 



of such incidents reported by these 46 persons was 3. Thirty- 
two of the 57 miners reported that they had been near the 
location of the rock fall only a few minutes prior to the time 
that the rock fell. 

These data suggest that unplanned rock falls in 
underground coal mines are a somewhat common event. Of 
the 143 miners interviewed for this study, 88 reported hav- 
ing had some type of recent experience with a rock fall. (This 
includes rock falls that produced injuries and those which 
were close enough to startle nearby miners.) Of these 88 
incidents, 66 occurred within approximately 25 ft of the face. 

It is surprising that 52 of these incidents occurred within 
only a few minutes after the miner had arrived at the area 
where the fall occurred. This suggests that it is very im- 
portant for miners to take the time to check the roof 
whenever they go to a new part of the mine. It suggests that 
many rock fall accidents could be avoided if miners would 
always check the roof before beginning to work in a new 
area. 



NATIONAL STATISTICS 

The injuries indicated in the statistics presented below 
are those in which a coal miner suffered an injury due to 
falling rock while working at an underground location. The 
data are derived from reports operators of U.S. coal mines 
submitted to MSHA concerning injuries their employees 
suffered while at work during 1980-84. Employers are re- 
quired by 30 CFR 50.2 to report to MSHA all injuries that 
cause an employee to miss one or more days of work. 
Employers are also required to report groundfalls and cer- 
tain other types of dangerous accidents to MSHA regardless 
of whether or not anyone was injured. During 1980-84, 
16,352 groundfall accidents were reported to MSHA by the 
operators of underground coal mines. These accidents 
resulted in 181 fatalities, 4,571 lost-time injuries, and 752 
injuries without lost time. 

The following list shows the percentage breakdown, by 
the nature of the injury, for the 4,571 lost-time accidents 
caused by groundfalls: 

Bruises and contusions . . 32.9 

Fractures and chips 21.1 

Multiple injuries 17.2 

Cuts and lacerations 9.2 

Sprains and strains 8.2 

Other 11.5 

These data suggest that groundfalls often produce relatively 
severe types of injuries, including broken bones and serious 
cuts. The average number of workdays lost following these 
injuries was 35.3 days. 

Frequency breakdowns of the injury data are presented 
below for the following variables: the location of the rock 
fall, the type of task being performed, the victim's job 
classification, the victim's length of experience as a coal 
miner, length of experience in the current job classification, 
and the amount of time that had elapsed since the shift 
began. 

Table 7 breaks down groundfall accidents by the loca- 
tion of the accident. These data suggest that intersections 
are the most common site of groundfall occurrences. About 



15 



Table 7.— Breakdown of groundfall accidents (1980-84), by 
location, percent 



Location 


Accidents 

without 

injury 


Injuries 


Fatalities 


Face 

Intersections 

Other 

Total number 


11.2 
52.5 
36.3 

10,848 


52.2 
10.1 
37.7 

5,323 


60.8 
19.3 
19.9 

181 



half of the groundfalls occurred in intersections, as well as 
roughly 1 in 5 groundfall fatalities. However, the most com- 
mon location for miners to be injured or killed by a ground- 
fall is the face area. Two of the main reasons that most in- 
juries and fatalities occur in face areas are that (1) the face 
often contains unsupported roof, and (2) more worker-hours 
are worked in face areas than in other areas of the mine. 
Table 8 breaks down injuries and fatalities caused by 
rock falls by the type of activity being performed. The data 
indicate that the types of activities most commonly being 
performed at the time of an injury -producing rock fall were 
handling supplies; roof bolting; barring down rock; idle or 
observing operations; setting, removing, or relocating props; 
and operating a continuous miner. Activities accounting for 
at least 5 pet of the fatalities were roof bolting; setting, 
removing, or relocating props; operating a continuous 
miner; idle or observing operations; handling supplies; 
timbering or cribbing; barring down rock; and walking. The 
14 activities listed in table 8 accounted for about three- 
fourths of all injury -producing rock falls and about four- 
fifths of all groundfall fatalities. As one might expect, most 
fatalities occurred during the installation or removal of 
devices to support the roof or rib. Activities associated with 
groundfall fatalities are discussed further in a later section. 



Table 8.— Breakdown of injuries and fatalities caused by 
rock falls (1 980-84), by activity, percent 

Activity Injuries Fatalities 

Handling supplies 10.8 7.8 

Roof bolting 10.2 13.2 

Barring down rock 8.0 5.0 

Idle or observing 

operations 7.6 8.3 

Setting, removing, or 

relocating props 6.0 . 9.4 

Operating continuous 

miner 5.8 8.8 

Walking 4.8 5.0 

Machine repair and 

maintenance 4.3 3.3 

Timbering or cribbing . . 4.2 7.2 

Moving power cable ... 3.3 2.8 
Shoveling or hand 

loading rock or coal . . 3.1 3.9 

Operating shuttle car . . . 2.3 0.6 

Operating scoop 2.2 3.9 

Setting brattice 2.2 1.1 

Other 25.2 19.7 

Total number 5,504 181 



The data in table 9 show that roof bolters accounted for 
a far greater percentage of fatalities than any other job. The 
most frequent victims of groundfall fatalities were bolters, 
laborers, helpers, and miner operators. Together, they ac- 
counted for 55.7 pet of the fatalities. An unusual finding 
was that although supervisors accounted for only 7.6 pet 
of all groundfall injuries during 1980-84, they accounted 
for 13.4 pet of all fatalities caused by groundfalls. Because 
supervisors may feel that it is their responsibility to ensure 



that their crews do not get hurt, they may tend to perform 
unusually hazardous tasks themselves rather than expose 
one of their crew to the danger. 

Table 9. — Breakdown of injuries and fatalities caused by 
rock falls (1980-84), by job title, percent 

Job title Injuries Fatalities 

Roof bolter iTI 23^8 

Roof bolter helper 4.5 5.5 

Continuous miner 

operator 8.4 5.5 

Continuous miner 

helper 6.6 9.9 

Laborer, face advance 

worker 14.2 11.0 

Section supervisor 2.8 5.0 

Laborers' supervisor ... 2.7 5.0 

Mine supervisor or 

superintendent 2.1 3.4 

Shuttlercar operator .... 6.4 2.8 

Timber worker, jack- 
setter 5.5 5.6 

Mechanic, repair 

worker 4.4 1.1 

Scoop operator 3.8 5.5 

Other 21.2 15.9 

Total number 5,504 181 



Table 10 breaks down injuries due to rock falls by the 
years of experience the victim had in his or her current job 
classification and his or her total years of experience as a 
coal miner. There appeared to be a steady increase in the 
number of injuries per year of mining experience for each 
of the first 6 yr. After these first 6 yr, there was a trend 
toward declining numbers of injuries. One reason for the 
initial low numbers of injuries was that the number of new 
miners entering the work force during 1980-84 was lower 
than in most other time periods. Another reason may have 
been that miners are not usually assigned to work in face 
areas when they are first hired and therefore are not as 
likely to be exposed to areas of unsupported roof. 



Table 10.— Breakdown of injuries caused by rock falls 

(1980-84), by experience as a miner and experience in 

current job classification, percent 

Experience, Injuries broken down by experience — 

yr As a coal miner At current type of job 

0-1 5.9 33.0 

1-2 7.5 18.8 

2-3 8.4 11.7 

3-4 8.5 7.9 

4-5 8.9 7.2 

5-6 9.4 5.4 

6-7 7.8 2.5 

7-8 7.0 2.9 

8-9 5.3 1 .6 

9-10 6.6 2.5 

10+ 24.7 5.5 

Total number. . . 5,033 4,400 



The breakdown of injuries by number of years of ex- 
perience performing the current job shows a pattern of con- 
tinual decline. Almost one-third of all groundfall injuries 
were suffered by miners who were in their first year on a 
new job. One reason why those with so little job experience 
accounted for most of the accidents may be that learning 
a new job requires that the miner devote less attention to 
avoiding hazards. This is because, during the learning 
stage, effective job performance requires a relatively greater 
amount of attention to new tasks than later, when task per- 
formance becomes more habitual. The decrease in injuries 
with greater job experience may also reflect the fact that 



16 



it takes time for miners to learn to recognize rock hazards 
in new areas of the mine in which their new job requires 
them to work. However, it would be necessary to collect ad- 
ditional data to determine the validity of these two possible 
explanations for the trend observed. It could also be that 
the decline in injuries with increased job experience merely 
reflected the fact that there were fewer mines who had 
higher amounts of job experience. 

Table 11 breaks down the injuries caused by rock falls 
by the time elapsed since the shift began. This data shows 
that most rock fall injuries occurred during the third and 
fourth hours after the shift began. Injuries during the fifth 
hour were 4.5 pet lower than those for the preceding hour. 
This relatively large drop in injuries may be largely due 
to a tendency for miners to be absent from the face area 
for at least a part of this hour while they take a mid-shift 
break from work. 



Table 1 1 .—Breakdown of injuries caused by rock falls 
(1980-84), by time elapsed since the shift began, percent 

Time, h Injuries 

0-1 3.7 

1-2 12.2 

2-3 16.3 

3-4 16.7 

4-5 12.2 

5-6 12.9 

6-7 13.8 

7-8 8.7 

Over 8 12.1 

Total number 5,419 



ANALYSIS OF DATA FROM MSHA 
FATALITY REPORTS 

MSHA's reports on 97 deaths caused by groundfalls in 
coal mines during 1979 and 1980 were reviewed in order 
to better understand the conditions or events which may 
have contributed to these accidents. Nearly all of the vic- 
tims were found at or near the face area, and most of them 
were beneath unsupported roof. Table 12 summarizes what 
rock fall victims were probably doing at the time the rock 
fell. As might be expected, most fatalities occurred during 
the installation or removal of devices to support the roof. 
A somewhat unexpected finding was that many victims (13 
pet) were reported to have been passively watching someone 
else work at the time of the accident. 



Table 1 2.— Breakdown of fatalities caused by rock falls 
(1979-80), by activity 

Number 

Installing posts, jacks, cross bars, rib boards 17 

Observing someone else work 13 

Operating equipment 8 

Removing jacks and posts 7 

Installing roof bolts 6 

Hand loading or shoveling ore 4 

Attending to trailing cable from continuous miner 4 

Waiting to bolt 3 

Marking roof for bolts 3 

Scaling roof 3 

Drilling holes for roof bolts 2 

Walking 2 

Examining broken jack 1 

Spraying continuous miner while operating 1 

Carrying supplies 1 

Repairing cable to continuous miner 1 

Examining area recently mined out 1 

Testing roof with pick 1 

Talking 1 

Inserting a bolt 1 

Unknown 16 

Total 97 

Given the high degree of interdependency among many 
mining tasks, it is not uncommon for miners to have to wait 
for short periods of time for their coworkers to finish a task 
before they can resume working. One might speculate that 
the reason individuals are so often hurt by roof falls while 
watching someone else is that, because they are absorbed 
in what someone else is doing, they stop attending to cues 
concerning hazards in their immediate environment. Also, 
there may be a tendency for individuals to falsely experience 
a sense of safety when they are in a passive state. It is likely 
that most injuries are perceived to be in some way the result 
of an act the victim performs which affects his or her en- 
vironment. Thus, the person who is inactively standing 
under dangerous roof may feel secure, and may not be likely 
to expect or search for sources of danger. Other major types 
of activities being performed at the time of a roof fall fatality 
were equipment operation, manual loading of coal, and 
monitoring the trailing cable from the continuous miner. 

Because roof bolters account for such a large portion of 
the fatalities (21 pet), an attempt was made to discover the 
phase of the bolting operation during which each bolter was 
killed. The fatality reports indicated that five bolters were 
installing timbers, posts or jacks; three were standing idle; 
two victims were marking the roof for bolts; two were drill- 
ing holes for bolts; two were removing temporary supports; 
two were walking; one was inserting a bolt; and one was 
scaling the roof. This suggests that the most dangerous 
phase of a bolter's job is the installation of temporary 
supports. 



DISCUSSION 



The information obtained from miners and MSHA in- 
spectors and presented in this report helps to better define 
the types of factors contributing to groundfall accidents, pro- 
vides a valuable reference base, and offers direction for 
future research in this area. 

A major strength of this report is that it is based on in- 
formation obtained from people who work underground. 
They are an invaluable source of information about barriers 
to miners' prevention of groundfall accidents. These peo- 
ple are in a unique position to explain why miners 
sometimes neglect potentially hazardous roof problems, why 
they sometimes go beneath unsupported roof, how often 



miners are going beneath unsupported roof, and what might 
be done to overcome barriers to miners' prevention of ac- 
cidents. However, the answers given in the interviews do 
not totally reflect "truth" or "reality." There is a variety 
of cognitive limitations and motivational biases which 
shape the way people make sense of the world around them. 
In interpreting and understanding the data from this study, 
it is important to keep in mind that the miners interviewed 
were subject to a variety of such limitations and biases. 
However, given that there are no obvious reasons why the 
participants in this study would have wanted to provide 
distorted answers to the questions they were asked, and 



17 



•^iven that they are the people whose decisions and actions 
most directly prevent or fail to prevent groundfall accidents, 
their assessment of the problem and potential solutions 
should most definitely be considered an informative and in- 
sightful source of information. 



BARRIERS TO ACCIDENT PREVENTION 

The data collected for this study suggest that most peo- 
ple who work in underground coal mines agree that the fac- 
tors listed in figure 1 are significant barriers to miners' 
prevention of groundfall accidents. The evidence supporting 
this assertion is reviewed below. 



Inability To Recognize Hazards 

The reasons for an individual's inability to recognize 
groundfall hazards may be an attribute of the person or of 
the environment. Data supporting the importance of this 
set of factors comes from miners' responses to questions C.l, 
C.2, and C.4. Forty-four percent said better lighting would 
help miners avoid rock fall injuries to a large or very large 
degree. This implies that miners may often fail to recognize 
hazardous roof conditions because the illumination is not 
good enough for them to be able to detect the hazardous con- 
ditions. Fifty-six percent said less noise would help miners 
to a large or very large degree. This implies that there may 
often be too much noise for miners to hear sounds that could 
warn them that a hazardous roof condition exists. Sixty- 
eight percent said better training in the identification of 
roof hazards would help miners to a large or very large 
degree. This suggests that miners sometimes fail to 
recognize certain types of hazardous roof conditions because 
they are not aware that these roof conditions should be con- 
sidered hazardous. 



Inability To Correct Hazards 

Data supporting the importance of this set of factors 
comes from miners responses to reasons A.l and A.6 and 
question C.6. Fifty -one percent agreed that one of the main 
reasons miners sometimes neglect correcting roof hazards 
is that they don't have the tools or materials with them that 
are needed to correct the roof problem. Thirty-seven per- 
cent agreed that one of the main reasons miners sometimes 
neglect to correct roof hazards is that they don't know how 
to correct roof problems. This suggests that miners 
sometimes fail to correct certain types of hazardous roof 
problems because they have never learned how to correct 
them. Sixty-nine percent said better training in proper 
methods of supporting the roof would help miners avoid rock 
fall injuries to a large or very large degree. 



Motivation To Search for Hazards 

Data supporting the importance of this set of factors 
comes from miners' responses to reasons A.8 and A.7 and 
question C.3. Eighty-one percent agreed that one of the 
main reasons miners sometimes neglect to correct roof 
hazards is that they don't take enough time to look for roof 
problems. One reason miners might not take enough time 
to look for roof problems is that they do not realize how 



dangerous roof problems are. In response to reason A.7, 68.4 
pet agreed that one of the main reasons miners sometimes 
neglect to correct roof hazards is that they don't realize how 
dangerous roof problems are. Another reason miners might 
not take enough time to look for roof problems is that they 
may not think their supervisor wants them to devote much 
time to this activity. In response to question C.3, 56 pet in- 
dicated that "supervisors putting greater emphasis on cor- 
recting roof hazards" would help miners avoid rock fall in- 
juries to a large or very large degree. However, in response 
to reason A.5, 89 pet disagreed with the statement, "One 
of the main reasons miners sometimes neglect to correct 
roof hazards is that they believe their supervisor thinks tak- 
ing care of roof problems in unimportant." This suggests 
that some supervisors need to place greater emphasis on 
this activity. 



Motivation To Correct Hazards 

Data supporting the importance of five types of factors 
within this category come from the miners' responses to 
reasons A.2, A.3, A.4, and A.7 and question C.3. Fifty-one 
percent agreed that one of the main reasons miners 
sometimes neglect to correct roof hazards is that they think 
it is someone else's responsibility to take care of roof prob- 
lems. Forty-eight percent agreed that one of the main 
reasons miners sometimes neglect to correct roof hazards 
is that they don't want to risk getting hurt while fixing the 
roof. Fifty-eight percent agreed that one of the main reasons 
miners sometimes neglect to correct roof hazards is that 
they dislike doing the type of work necessary to correct the 
roof problem. Sixty-eight percent agreed that one of the 
main reasons miners sometimes neglect to correct roof 
hazards is that they don't realize how dangerous roof prob- 
lems really are. Fifty-six percent indicated that "supervisors 
putting greater emphasis on correcting roof hazards" would 
help miners avoid rock fall injuries to a large or very large 
degree. 



WALKING BENEATH UNSUPPORTED ROOF 

At least 50 pet of the miners agreed with each of five 
statements about why miners walk beneath unsupported 
roof. These responses suggest that most miners believe the 
main reasons why people walk beneath unsupported roof 
include: (1) They do it inadvertently; (2) they believe it is 
safe to do it; (3) they are trying to save time; (4) it takes 
too much effort to set temporary supports; and (5) it is con- 
sidered an acceptable practice by coworkers. Eighty-eight 
percent of the miners said they believe that most miners 
do not walk beneath unsupported roof before looking at it 
carefully, suggesting that most miners who walk beneath 
unsupported roof are somewhat fearful of being struck by 
a roof fall. 

The median of miners' estimates of the percentage of 
miners who go beneath unsupported roof during a typical 
month was 10 pet. Forty-four percent indicated that they 
believe someone goes beneath unsupported roof at least once 
per shift, and 25 pet indicated that they believe someone 
goes beneath unsupported roof at least once per week. 
Taken together, these estimates suggest (1) few miners are 
going beneath unsupported roof, but that (2) those who are 
going beneath unsupported roof are doing it rather often. 



18 



MINERS' AND INSPECTORS' RECOMMENDATIONS 
FOR PREVENTING GROUNDFALL ACCIDENTS 

When asked what should be done to reduce the number 
of rock fall accidents in the coal industry, miners frequently 
replied that better training was needed and that miners 
should somehow be motivated to inspect the roof more often. 
MSHA inspectors often said that the use of automated tem- 
porary roof support (ATRS) systems on bolters should be 
made mandatory; training should be improved; remote sens- 
ing devices should be used to check for gas at the face; con- 
tinuous miner operators should be encouraged to report roof 
problems to bolters more often; and roof control plans need 
to be followed more closely. 

The need for better training was mentioned frequently 
by both inspectors and miners. With regard to improving 
training, inspectors recommended the following: (1) Supple- 
ment classroom training with structured on-the-job train- 
ing in roof control and the identification of groundfall 
hazards; (2) explain the theoretical principles of roof sup- 
port in lay terms; (3) limit the size of training classes to en- 
courage more discussion; and (4) increase miners' awareness 
of the consequences of roof falls by showing slides of roof 
fall accidents and relating the details of how people have 
been injured by them. 

Most miners stated that the following proposed changes 
would significantly help miners avoid rock fall injuries: less 



noise, supervisors putting greater emphasis on correcting 
roof hazards, better training in the identification of roof 
hazards, better training in proper methods of supporting 
the roof, reprimanding or penalizing those who repeatedly 
go beneath unsupported roof, better scaling of the roof, add- 
ing more support to bad areas of the roof, and better installa- 
tion of roof bolts. 



MINERS' EXPERIENCES WITH GROUNDFALL 
ACCIDENTS 

Unplanned rock falls in underground coal mines are a 
somewhat common event. Eighty-eight of the 143 miners 
interviewed reported that they had either been injured by 
or startled by a rock fall at least one time during the past 
year. Eighty-one percent of those who reported that they 
had been recently startled by large pieces of falling rock 
said that such an incident had happened more than once 
within the past year. The median for these incidents was 
three times. Sixty -five percent of the miners who reported 
that they had recently suffered an injury caused by a 
groundfall said they had been near the location of the rock 
fall for only a few minutes prior to the accident. This sug- 
gests that most rock fall accidents could be avoided if miners 
would always check the roof before beginning to work in 
a new area. 



19 



APPENDIX.— ROOF FALL INTERVIEW GUIDE FOR MINERS 



Interviewee: 

Interviewer: 

Shift: 

0000-0800 

0800-1600 

1600-2400 



Date: 

Name of mine: 

Section: 



1. INTRODUCTION TO MINER QUESTIONNAIRE 

. I'm part of the group from the Bureau of Mines in Pittsburgh that is here 



Hello, my name is 

to do some interviews with miners and mine management. 

During this interview, I'm going the ask for your opinions about the causes of roof fall accidents, and what you think 
could be done to help prevent them. 

Your participation is completely voluntary. You need not answer every question. 

Anything that you do tell us will be held in strict confidence. By that I mean that nothing that you will say will be iden- 
tified with you. Any report that is written will not identify any single miner's particular answer. For example, we might 
report that 90% of the miners at mine X believe roof falls are hard to predict. 

Each miner will receive a summary of what the miners at his or her mine think about the causes and prevention of roof 
fall accidents. This summary will also provide information about what miners at other mines think about roof fall accidents. 
You may be curious about why we've chosen to talk to people from the mine where you work. Your mine is one of several 
mines that are part of our study. It was chosen because it met certain characteristics of size, type of mining technique, 
and location. 

At this point, do you have any questions? 



2. JOB HISTORY 

Before beginning the questions about roof falls, I'd like to get some information about your experience as a miner. 

2.1 What is your present job? 

2.2 How long have you been on that job? 
(If more than a month, go to 2.3.) 

(If less than a month, go to 2.2a.) 

2.2a Is this a permanent or temporary assignment? P T 

If temporary, ask: 

2.2b What is your regular job? 



20 

2.2c How long have you held that job? 

2.3 How long have you worked in the section where you now work? 

2.4 Altogether, how many years have you worked as a coal miner? 

The new few questions are about your experience with performing roof control activities. 
(If the miner is a bolter or bolter helper, skip to 2.7.) 

2.5 During the past 6 months, did you help install any type of roof support? 

Y N 

(If yes, ask, "What types of roof support did you install?") 

2.6 Have you ever worked as a roof bolter or bolter helper? Y N 
(If yes, ask "How long were you a bolter or bolter helper?") 

2.7 About how many days per week do you spend some time scaling the roof? 
12 3 4 5 

2.8 About how many days per week do you spend some time sounding the roof? 
12 3 4 5 

3. EXPERIENCE WITH ROOF FALLS 

3.1.1 Within the past 2 yr, have you had a lost-time injury as a result of being struck by pieces of falling rock? 

Y N (If no, go to 3.2.) 

3.1.2 During the past year, have you been injured, bruised, or in any way hurt by pieces of rock falling from the roof or rib? 

Y N (If no, go to section 3.A.) 

3.2 How long ago did this happen? 

3.3 What type of injury did you suffer? 

3.4 Which of these best describes where you were when you were injured: 

A. within 25 ft of the face 

B. in a working section but not at the face 

C. not in a working section (ask "Where were you?") 

3.5 Did the rock fall in an area of roof that was supported or unsupported? 
S U 

If supported, ask, "What type of roof supports were being used at the place where the rock fell?" 

3.6 What type of job were you doing on the day you were injured? 

3.7 What were you doing at the moment the rock struck you? 

3.8 On the day that the rock fell, about how many hours or minutes had you spent near the location of the rock fall 
before the fall actually occurred? 

(Probes: most of the shift? 

less than half the shift? 
only a few minutes?) 



21 

3.9 During that time, did you notice anything unusual about the condition of the roof? 

Y N 

If yes, ask, "Please describe what you noticed that was unusual?" 

3.10 Considering the week before the time that the rock fell, had the area where the rock fell been heavily traveled, 
lightly traveled, or not traveled at all? 

H L N 

3.11 Was anything unusual going on the day of the rock fall that might have distracted you, or caused you to pay less 
attention to the condition of the roof than usual? 

3.12 Was there any noise coming from nearby tools or equipment at the time the rock fell? 

Y N 

(If yes, specify source and distance.) 

3.13 Was there any source of light in the area where the rock fell other than your cap lamp? 

Y N 

(If yes, specify source and distance.) 

3.14 Altogether, how many times during the past 6 months have you been close enough to large pieces of falling rock 
that they startled or surprised you? 

(Go to section 4.) 

Section 3.A— Experience With Roof Falls— No Injury 

3.1 Within the past year, have you been close enough to large pieces of falling rock that they startled or surprised you? 

Y N 

(If yes, go to 3.4.1.) 

3.2 Within the past 6 months, has anyone told you that they came close to being hurt by falling rock? 

Y N 

(If no, go to section 4.) 

3.3 What did they say about the rock fall? 
(Go to section 4.) 

3.4.1 How many times within the past year has this happened? 

3.4.2 I'd like to ask you some questions about the most recent time you were surprised by falling rock. How long ago 
was the most recent time that this happened? 

3.5 Which of these best describes where you were when the rock fell: 

A. within 25 feet of the face 

B. in a working section but not at the face 

C. not in a working section (ask "Where were you?") 

3.6 Did the rock fall in an area of roof that was supported or unsupported? 
S U 



22 

If supported, ask, "What type of roof supports were being used at the place where the rock fell?" 

3.7 What type of job were you doing on the day of the rock fall? 

3.8 What were you doing at the moment the rock fell? 

3.9 On the day that the rock fell, about how many hours or minutes had you spent near the location of the rock fall 
before the fall actually occurred? 

(Probes: most of the shift? 

less than half the shift? 
only a few minutes?) 

3.10 During that time, did you notice that anything was unusual about the condition of the roof? 

Y N 

If yes, ask, "Please describe what you noticed that was unusual." 

3.11 Considering the week before the time that the rock fell, had the area where the rock fell been heavily traveled, 
lightly traveled, or not traveled at all? 

H L N 

3.12 Was anything unusual going on the day of the rock fall that might have distracted you, or caused you to pay less 
attention to the condition of the roof than usual? 

3.13 Was there any noise coming from nearby tools or equipment at the time the rock fell? 

Y N 

(If yes, specify source and distance.) 

3.14 Was there any source of light in the area where the rock fell other than your cap lamp? 

Y N 

(If yes, specify source and distance.) 

4. NONRESPONSE TO POSSIBLE ROOF HAZARDS 

The next few questions are about why miners sometimes neglect to correct hazardous roof conditions. At one time or 
another, most miners have seen areas of the roof that look like they may not be entirely safe, but for some reason, do 
not do anything about it. 

What are the major reasons why miners sometimes fail to do anything about potential roof hazards? 

I'm going to read a list of reasons why miners might not do anything about potentially hazardous roof conditions. As 
I read each one, I'd like you to tell me the extent to which you agree or disagree that it explains why miners sometimes 
fail to respond. Please use the numbers on this response card for your answers. As you can see, the answers on this card 
range from 1, for strongly agree, to 6, for strongly disagree. 

RESPONSE CARD 

1. strongly agree 

2. agree 

3. slightly agree 

4. slightly disagree 

5. disagree 

6. strongly disagree 

(EXAMPLE: The fishing around here is good.) 

One of the main reasons miners sometimes neglect to correct roof hazards is that— 

4.1 they don't have the tools or materials with them that are needed to fix the roof problem. 



23 

4.2 they think it is someone else's responsibility to take care of roof problems. 

4.3 they don't want to risk getting hurt while fixing the roof. 

4.4 they dislike doing the type of work necessary to correct the roof problem. 

4.5 they believe their supervisor thinks that taking care of roof problems is unimportant. 

4.6 they don't know how to correct roof problems. 

4.7 they don't realize how dangerous roof problems are. 

4.8 they don't take enough time to look for roof problems. 

5. WORKING BENEATH UNSUPPORTED ROOF 

The next set of questions are about working beneath unsupported roof. The only legally permissible reason for going 
beneath unsupported roof is to set temporary supports before bolting. However, miners sometimes go beneath unsup- 
ported roof for reasons other than to set temporary supports. We are interested in knowing more about these other reasons. 
So, please base your answers to these next few questions on the times when miners go beneath unsupported roof for reasons 
other than to set temporary supports. I'm going to read several statements about going beneath unsupported roof. Using 
the response card, I'd like you to tell me the extent to which you agree or disagree with each of these statements. 

One of the main reasons miners sometimes walk beneath unsupported roof is that— 

5.1 they do not realize they have gone beyond the edge of roof that is properly supported, and do not intend to do so. 

5.2 they do not believe it is unsafe to do so. 

5.3 they are trying to save time. 

5.4 it takes too much effort to set temporary supports. 

5.5 they have often seen other people do it. 

5.6 most miners do not walk beneath unsupported roof before looking at it carefully. 

RESPONSE CARD 

1. strongly agree 

2. agree 

3. slightly agree 

4. slightly disagree 

5. disagree 

6. strongly disagree 

5.8 During a typical month, what percentage of miners who work at the face go beneath unsupported roof for reasons 
other than to set temporary supports? 

5.9 Considering a typical crew of miners who work at the face, how often does someone go beneath unsupported roof 
for reasons other than to set temporary supports? 

(once a shift? week? month?) 

6. TECHNIQUES FOR REDUCING ROOF FALL ACCIDENTS 16887 285 

The next few questions are about things that could be done to reduce roof fall accidents. 

What do you think should be done to reduce the number of roof fall accidents in the coal industry? 

I'm going to read a list of things that might be done to help miners avoid roof fall injuries. Using this new response card, 
I'd like you to rate the degree to which each of the following would help miners to avoid roof fall injuries. As you can 
see, the answers on this card range from 1, a very small degree, to 6, a very large degree. 



24 

To what degree would help miners avoid rock fall injuries? 

6.1 better lighting 

(If miner replies with 5 or 6, ask, "How could the lighting be improved?") 

6.2 less noise 

6.3 supervisors putting greater emphasis on correcting roof hazards 

6.4 better training in the identification of roof hazards 

6.5 better training in proper methods to support the roof 

6.6 reprimanding or penalizing those who repeatedly go beneath unsupported roof 

6.7 better scaling of the roof 

6.8 adding more support to bad areas of the roof 

6.9 better installation of roof bolts 

RESPONSE CARD 

1. a very small degree 

2. a small degree 

3. a somewhat small degree 

4. a somewhat large degree 

5. a large degree 

6. a very large degree 

7. DEMOGRAPHICS 

The last three questions concern your age, marital status, and dependents. 

What is your age? 

Do you have any children? Y N 

Are you currently married? Y N 

Thank you for helping us with this study. 






a V "^ ^ 

.9 »V°' v 



4> ^ 






f\ '■'■ 






ts ^ \ ° 

4 A & 



«> A" 



! X 



<, 



••. 1 



J, * «/ «^ 



^ 



i 



*0 'o. »* A <> 

*6$ 



"oV' 



> ^ -: 









% 









-P. 



/' "v-WV V-^-> V^V V-- 8 ---/ V*"--*> V 







o V 




1 MAY-JUNE 1987 f. * * * a G ^ ^ 



p- / X'W'S VW \w/* \- ... ,- .. -, 

r /.^>>o .y,^.^. o°*.^-.^ .^.■^■^ c° ••^.:, 




<iM 



^m 



1 1 

■ 
^1 



I 

' m 

■ 












♦ I 







K,w., 








H 














■ 



I I 



I 















_ i ,-*'i 



LIBRARY OF CONGRESS 







002 953 951 



